package com.kuang.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.multipart.commons.CommonsMultipartFile;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.net.URLEncoder;

/**
 * @program: SpringMVC
 * @description:
 * @author: 陈恩涛
 * @create: 2020-08-09 20:51
 **/
@Controller
public class FileController {

    //@RequestParam("file") 将name=file控件得到的文件封装成CommonsMultipartFile对象
    //批量上传CommonsMultipartFile则为数组即可
    @RequestMapping("/upload")
    public String fileUpload(@RequestParam("file") CommonsMultipartFile file, HttpServletRequest request) throws IOException {

        //获取文件名：file.getOriginalFilename()
        String uploadFileName = file.getOriginalFilename();

        //如果文件名为空，直接回到首页
        if ("".equals(uploadFileName)) {
            return "redirect:/index.jsp";
        }
        System.out.println("上传文件名：" + uploadFileName);

        //上传路径保存设置
        String path = request.getServletContext().getRealPath("/upload");
        //如果路径不存在，创建一个
        File realPath = new File(path);
        if (!realPath.exists()) {
            realPath.mkdir();
        }
        System.out.println("上传文件保存地址："+realPath);

        InputStream is = file.getInputStream();//文件输入流
        FileOutputStream fos = new FileOutputStream(new File(realPath, uploadFileName));//文件输出流

        //读取写出
        int len = 0;
        byte[] buffer = new byte[1024];
        while ((len = is.read(buffer)) != -1) {
            fos.write(buffer, 0, len);
            fos.flush();
        }
        fos.close();
        is.close();
        return "redirect:/index.jsp";
    }

    /*
     * 采用file.Transto    来保存上传的文件
     *
     * */
    @RequestMapping("/upload2")
    public String fileUpload2(@RequestParam("file") CommonsMultipartFile file, HttpServletRequest request) throws IOException {

        //上传路径保存设置
        String path = request.getServletContext().getRealPath("/upload");
        File realPath = new File(path);
        if (!realPath.exists()) {
            realPath.mkdir();
        }

        //上传文件地址
        System.out.println("文件上传保存地址：" + realPath);

        //通过CommonsMultipartFile的方法直接写入文件
        file.transferTo(new File(realPath + "/" + file.getOriginalFilename()));

        return "redirect:/index.jsp";
    }

    @RequestMapping("/download")
    public String downloads(HttpServletResponse response, HttpServletRequest request) throws Exception {
        //要下载的图片地址
        String path = request.getServletContext().getRealPath("/upload");
        String fileName = "1.png";

        //1、设置response响应头
        response.reset();//设置页面不缓存，清空buffer
        response.setCharacterEncoding("UTF-8");//字符编码
        response.setContentType("multipart/form-data");//二进制传输数据
        //设置响应头
        response.setHeader("Content-Disposition", "attachment;fileName=" + URLEncoder.encode(fileName, "UTF-8"));

        File file = new File(path, fileName);
        //2、读取文件--输入流
        FileInputStream input = new FileInputStream(file);
        //3、写出文件--输出流
        ServletOutputStream out = response.getOutputStream();

        byte[] buff = new byte[1024];
        int index = 0;
        //执行写出操作
        while ((index = input.read(buff)) != -1) {
            out.write(buff, 0, index);
            out.flush();
        }

        out.close();
        input.close();
        return null;
    }
}
